Automated Bleed-Off System for a Fluid System

The present disclosure relates generally to fluid systems and, for example, to an automated bleed-off system for a fluid system.

Hydraulic fracturing is a well stimulation technique that typically involves pumping hydraulic fracturing fluid into a wellbore at a rate and a pressure (e.g., up to 15,000 pounds per square inch (psi)) sufficient to form fractures in a rock formation surrounding the wellbore. This well stimulation technique often enhances the natural fracturing of a rock formation to increase the permeability of the rock formation, thereby improving recovery of water, oil, natural gas, and/or other fluids. In a hydraulic fracturing operation, pressurized fluid and proppants may be pumped into the wellbore in a series of stages. Following a stage, the pressurized fluid may be bled from the system to allow for various well completion activities (e.g., wireline activities) to be performed in the wellbore. Generally, in a bleed-off operation, one or more valves are manually opened and closed when a target pressure is reached. This manual approach is imprecise and inconsistent, which can lead to unintended rapid depressurization and damage to components of the hydraulic fracturing system. Moreover, the valves should receive frequent greasing to improve their longevity. However, a timing for greasing the valves is often subject to operator discretion, which can result in lengthy intervals between greasings that can shorten a useful life of the valves.

The automated bleed-off system of the present disclosure solves one or more of the problems set forth above and/or other problems in the art.

An automated bleed-off system for a hydraulic fracturing system may include a bleed-off manifold. The bleed-off manifold may include one or more fluid inputs to receive pressurized fluid from the hydraulic fracturing system, a bleed-off line fluidly coupling the one or more fluid inputs to an output, and a plurality of isolation valves to control flow through the one or more fluid inputs and the bleed-off line. The automated bleed-off system may include a valve greasing system that includes a grease reservoir to hold grease, and a grease conduit fluidly coupling the grease reservoir to an isolation valve of the plurality of isolation valves. The automated bleed-off system may include a control system that includes a valve actuator, including an actuation sensor, to control actuation of the isolation valve, and a controller configured to cause actuation of one or more of the plurality of isolation valves to bleed-off pressure via the bleed-off line.

A bleed-off manifold for a hydraulic fracturing system may include a first fluid input to receive pressurized fluid from a pump side of the hydraulic fracturing system. The pump side is upstream of a valve, in a conduit of the hydraulic fracturing system, that is between one or more pumps and one or more wells of the hydraulic fracturing system. The bleed-off manifold may include a second fluid input to receive pressurized fluid from a well side of the hydraulic fracturing system. The well side is downstream of the valve. The bleed-off manifold may include a bleed-off line fluidly coupling the first fluid input and the second fluid input to an output, where the bleed-off line includes a multi-stage choke assembly. The bleed-off manifold may include a bypass line fluidly coupling the first fluid input and the second fluid input to the output, where the bypass line bypasses the multi-stage choke assembly. The bleed-off manifold may include a first isolation valve to control flow through the first fluid input, a second isolation valve to control flow through the second fluid input, a third isolation valve to control flow through the bleed-off line, and a fourth isolation valve to control flow through the bypass line.

A method for automated bleed-off of fluid pressure from a hydraulic fracturing system between stages of a hydraulic fracturing operation may include obtaining, by a controller and after completion of a stage of the hydraulic fracturing operation, an instruction to bleed-off pressure from the hydraulic fracturing system, and causing, by the controller, opening of multiple isolation valves of a bleed-off manifold to bleed-off pressure via a multi-stage choke assembly in a bleed-off line of the bleed-off manifold.

This disclosure relates to an automated bleed-off system, which is applicable to any system that contains high-pressure fluid. For example, the system may be a hydraulic fracturing system.

1 FIG. 1 FIG. 1 FIG. 100 is a diagram illustrating an example hydraulic fracturing system. For example,depicts a plan view of an example hydraulic fracturing site along with equipment that is used during a hydraulic fracturing process. In some examples, less equipment, additional equipment, or alternative equipment to the example equipment depicted inmay be used to conduct the hydraulic fracturing process.

100 102 102 The hydraulic fracturing systemincludes a well. Hydraulic fracturing is a well-stimulation technique that uses high-pressure injection of fracturing fluid into the welland corresponding wellbore in order to hydraulically fracture a rock formation surrounding the wellbore. While the description provided herein describes hydraulic fracturing in the context of wellbore stimulation for oil and gas production, the description herein is also applicable to other uses of hydraulic fracturing.

104 106 100 104 108 108 108 108 108 108 108 108 100 100 106 108 High-pressure injection of the fracturing fluid may be achieved by one or more pump systemsthat may be mounted (or housed) on one or more hydraulic fracturing trailers(which also may be referred to as “hydraulic fracturing rigs”) of the hydraulic fracturing system. Each of the pump systemsincludes at least one fluid pump(referred to herein collectively, as “fluid pumps” and individually as “a fluid pump”). The fluid pumpsmay be hydraulic fracturing pumps. The fluid pumpsmay include various types of high-volume hydraulic fracturing pumps such as triplex or quintuplex pumps. Additionally, or alternatively, the fluid pumpsmay include other types of reciprocating positive-displacement pumps or gear pumps. A type and/or a configuration of the fluid pumpsmay vary depending on the fracture gradient of the rock formation that will be hydraulically fractured, the quantity of fluid pumpsused in the hydraulic fracturing system, the flow rate necessary to complete the hydraulic fracture, the pressure necessary to complete the hydraulic fracture, or the like. The hydraulic fracturing systemmay include any number of trailershaving fluid pumpsthereon in order to pump hydraulic fracturing fluid at a predetermined rate and pressure.

108 110 112 110 108 102 110 108 110 114 100 100 112 112 112 1 112 2 112 1 110 108 112 2 108 110 In some examples, the fluid pumpsmay be in fluid communication with a manifoldvia various fluid conduits, such as flow lines, pipes, or other types of fluid conduits. The manifoldcombines fracturing fluid received from the fluid pumpsprior to injecting the fracturing fluid into the well. The manifoldalso distributes fracturing fluid to the fluid pumpsthat the manifoldreceives from a blenderof the hydraulic fracturing system. In some examples, the various fluids are transferred between the various components of the hydraulic fracturing systemvia the fluid conduits. The fluid conduitsinclude low-pressure fluid conduits() and high-pressure fluid conduits(). In some examples, the low-pressure fluid conduits() deliver fracturing fluid from the manifoldto the fluid pumps, and the high-pressure fluid conduits() transfer high-pressure fracturing fluid from the fluid pumpsto the manifold.

110 116 116 110 116 110 102 102 116 The manifoldalso includes a fracturing head. The fracturing headmay be included on a same support structure as the manifold. The fracturing headreceives fracturing fluid from the manifoldand delivers the fracturing fluid to the well(via a well head mounted on the well) during a hydraulic fracturing process. In some examples, the fracturing headmay be fluidly connected to multiple wells.

114 118 120 100 118 120 122 100 120 The blendercombines proppant received from a proppant storage unitwith fluid, which may be received from a hydration unitof the hydraulic fracturing system. In some examples, the proppant storage unitmay include a dump truck, a truck with a trailer, one or more silos, or other types of containers. The hydration unitreceives water from one or more water tanks. In some examples, the hydraulic fracturing systemmay receive water from water pits, water trucks, water lines, and/or any other suitable source of water. The hydration unitmay include one or more tanks, pumps, gates, or the like.

120 114 114 100 124 124 120 114 The hydration unit, or alternatively a chemical adding unit or the blender, may add fluid additives, such as polymers or other chemical additives, to the water. Such additives may increase the viscosity of the fracturing fluid prior to mixing the fluid with proppant in the blender. The additives may also modify a pH of the fracturing fluid to an appropriate level for injection into a targeted formation surrounding the wellbore. Additionally, or alternatively, the hydraulic fracturing systemmay include one or more fluid additive storage unitsthat store fluid additives. The fluid additive storage unitmay be in fluid communication with the hydration unitand/or the blenderto add fluid additives to the fracturing fluid.

100 126 126 102 100 128 128 100 128 128 100 128 100 In some examples, the hydraulic fracturing systemmay include a balancing pump. The balancing pumpprovides balancing of a differential pressure in an annulus of the well. The hydraulic fracturing systemmay include a data monitoring system. The data monitoring systemmay manage and/or monitor the hydraulic fracturing process performed by the hydraulic fracturing systemand the equipment used in the process. In some examples, the management and/or monitoring operations may be performed from multiple locations. The data monitoring systemmay be supported on a van, a truck, or may be otherwise mobile. The data monitoring systemmay include a display for displaying data for monitoring performance and/or optimizing operation of the hydraulic fracturing system. In some examples, the data gathered by the data monitoring systemmay be sent off-board or off-site for monitoring performance and/or performing calculations relative to the hydraulic fracturing system.

100 130 130 100 104 130 104 130 100 The hydraulic fracturing systemincludes a controller. The controllermay be a system-wide controller for the hydraulic fracturing systemor a pump-specific controller for a pump system. The controllermay be communicatively coupled (e.g., by a wired connection or a wireless connection) with one or more of the pump systems. The controllermay also be communicatively coupled with other equipment and/or systems of the hydraulic fracturing system.

100 132 134 110 102 132 116 132 116 132 100 132 100 132 100 136 134 110 102 100 136 132 1 FIG. 2 FIG. The hydraulic fracturing systemmay include a valve(e.g., a check valve) in a conduitbetween the manifoldand the well. For example, the valveis shown indownstream of the fracturing head. However, in some examples, the valvemay be upstream of the fracturing head. The valvedefines a pump side (which can also be referred to as a “truck side”) of the hydraulic fracturing systemupstream of the valve, and a well side (which can also be referred to as a “wellhead side”) of the hydraulic fracturing systemdownstream of the valve. The hydraulic fracturing systemmay include an automated bleed-off systemfluidly coupled to the conduitbetween the manifoldand the wellto receive pressurized fluid from the hydraulic fracturing system. For example, fluid inputs of the automated bleed-off systemmay be fluidly coupled upstream and downstream, respectively, of the valve, as described further in connection with.

1 FIG. 1 FIG. As indicated above,is provided as an example. Other examples may differ from what is described with regard to.

2 FIG. 136 136 200 300 400 402 136 136 138 138 136 is a perspective view of an example of the automated bleed-off system. The automated bleed-off systemmay include a bleed-off manifold, a valve greasing system, and a control systemthat includes a controller. The components of the automated bleed-off systemmay be mounted in a frame or a housing (e.g., that fully or partially encloses the components). For example, the components of the automated bleed-off systemmay be mounted on a skid, as shown. The skidmay include lifting mechanism (e.g., forklift tubes and/or lifting eyelets) to facilitate transport of the automated bleed-off system.

2 FIG. 2 FIG. As indicated above,is provided as an example. Other examples may differ from what is described with regard to.

3 FIG. 200 200 202 204 100 206 202 204 208 200 200 202 100 132 204 100 132 is a top view of an example of the bleed-off manifold. The bleed-off manifoldmay include one or more fluid inputs,to receive pressurized fluid from the hydraulic fracturing system, and a bleed-off linefluidly coupling the one or more fluid inputs,to an outputof the bleed-off manifold. For example, the bleed-off manifoldmay include a first fluid inputto receive pressurized fluid from the pump side of the hydraulic fracturing system(i.e., upstream of the valve), and a second fluid inputto receive pressurized fluid from the well side of the hydraulic fracturing system(i.e., downstream of the valve).

206 202 204 208 206 210 210 210 210 210 210 210 210 210 210 210 210 210 210 210 210 206 200 210 210 210 a b a b a b a b a b a b a b a b The bleed-off linemay couple the first fluid inputand the second fluid inputto the output. The bleed-off linemay include a multi-stage choke assemblythat includes a first chokeand a second chokearranged in series. In some examples, the first chokemay have an elbow (or 90 degrees) configuration, while the second chokemay have an in-line (or straight) configuration. In some examples, the first chokeand the second chokemay include respective orifices that are fixed, during operation, with respect to a particular flow area that is provided. In other words, whereas orifice hardware may be interchangeable, during a maintenance period, to be configured to provide for certain changes in the flow area, the orifice hardware may be non-adjustable during operation. However, in some other examples, the first chokeand the second chokemay be adjustable during operation. The first chokeand the second chokemay include respective orifices having the same opening diameter (e.g., such that the first chokeand the second chokeprovide equivalent pressure reductions to the pressurized fluid). Alternatively, the respective orifices of the first chokeand the second chokemay have different opening diameters from each other. The multi-stage choke assemblyprovides a gradual pressure release through the bleed-off line, thereby extending a useful life of the bleed-off manifoldand of the chokes,. In some implementations, the multi-stage choke assemblymay include more than two chokes (e.g., three chokes, four chokes, or five chokes) to provide additionally gradual pressure release.

200 212 212 202 204 208 212 202 204 208 206 212 210 In some implementations, the bleed-off manifoldmay include a bypass line. The bypass linemay couple the first fluid inputand the second fluid inputto the output. The bypass linemay provide a fluid path from the inputs,to the outputthat bypasses the bleed-off line. In particular, the bypass linemay bypass the multi-stage choke assembly.

200 214 216 218 220 214 216 218 220 202 204 206 212 200 214 202 216 204 218 206 220 212 214 216 218 220 The bleed-off manifoldmay include a plurality of isolation valves,,, and. The isolation valves,,, andmay control fluid flow through the fluid inputs,, the bleed-off line, and/or the bypass line. For example, the bleed-off manifoldmay include a first isolation valveto control flow through the first fluid input, a second isolation valveto control flow through the second fluid input, a third isolation valveto control flow through the bleed-off line, and a fourth isolation valveto control flow through the bypass line. The isolation valves,,, andmay be plug valves or another type of valve.

214 216 218 220 222 222 222 224 224 200 222 224 214 222 224 216 222 224 218 222 224 220 Each isolation valve,,,may include a valve actuatorto control actuation (e.g., opening and closing) of the isolation valve. A valve actuatormay provide automated actuation of an isolation valve using a hydraulic, pneumatic, or electronic actuation mechanism. Each valve actuatormay include an actuation sensor(e.g., a position sensor) configured to detect actuation of an isolation valve. For example, an actuation sensormay measure a degree of actuation of an isolation valve (e.g., 20% open, 50% open, 80% open, etc.), or simply whether the isolation valve has been actuated (e.g., whether the valve has been opened or closed). In some examples, the bleed-off manifoldmay include a first valve actuator, with a first actuation sensor, to control actuation of the first isolation valve, a second valve actuator, with a second actuation sensor, to control actuation of the second isolation valve, a third valve actuator, with a third actuation sensor, to control actuation of the third isolation valve, and a fourth valve actuator, with a fourth actuation sensor, to control actuation of the fourth isolation valve.

200 226 202 204 226 226 206 212 226 226 226 202 204 206 212 214 216 218 220 a b In some examples, the bleed-off manifoldmay include a connection conduit. The fluid inputs,may be fluidly coupled to an input endof the connection conduit. The bleed-off lineand the bypass linemay be fluidly coupled to an output endof the connection conduit. In this way, the connection conduitenables distribution of fluid from either of the first fluid inputor the second fluid inputto either of the bleed-off lineor the bypass line(e.g., depending on which isolation valves,,,are open).

200 228 200 200 228 202 214 202 200 228 204 216 204 200 228 214 216 214 216 226 228 214 216 In some examples, the bleed-off manifoldmay include one or more pressure sensors(e.g., pressure transducers) to measure pressures in the bleed-off manifold. For example, the bleed-off manifoldmay include a first pressure sensor, which may be positioned between the first fluid inputand the first isolation valve, to measure a pressure at the first fluid input. The bleed-off manifoldmay include a second pressure sensor, which may be positioned between the second fluid inputand the second isolation valve, to measure a pressure at the second fluid input. The bleed-off manifoldmay include a third pressure sensor, which may be positioned between the first isolation valveand the second isolation valve, to measure a pressure between the first isolation valveand the second isolation valve(e.g., a pressure in the connection conduit). As another example, the third pressure sensorcan be used to detect whether the first isolation valveand/or the second isolation valvehas a leak.

200 230 232 200 234 202 228 234 232 214 230 236 204 228 236 232 216 230 228 230 226 226 230 226 226 232 206 218 232 212 220 232 206 212 238 208 200 a b a b In one configuration, the bleed-off manifoldmay include a four-way connector(e.g., a cross connector) and a three-way connector(e.g., a tee connector) that couple conduits of the bleed-off manifold. A conduitthat includes the first fluid input, the first pressure sensor(e.g., coupled in the conduitby an additional three-way connector), and the first isolation valvemay be fluidly coupled to a first port of the four-way connector. A conduitthat includes the second fluid input, the second pressure sensor(e.g., coupled in the conduitby an additional three-way connector), and the second isolation valvemay be fluidly coupled to a second port of the four-way connector(e.g., that is opposite the first port). The third pressure sensormay be fluidly coupled to a third port of the four-way connector. The input endof the connection conduitmay be fluidly coupled to a fourth port of the four-way connector(e.g., opposite the third port), and the output endof the connection conduitmay be fluidly coupled to a first port of the three-way connector. The bleed-off line, including the third isolation valve, may be fluidly coupled to a second port of the three-way connector. The bypass line, including the fourth isolation valve, may be fluidly coupled to a third port of the three-way connector(e.g., opposite the second port). The bleed-off lineand the bypass linemay converge at a conduitthat terminates at the output. Various components of the bleed-off manifolddescribed herein may be connected to each other by threaded connections or another type of connection that provides fluid tightness.

3 FIG. 3 FIG. As indicated above,is provided as an example. Other examples may differ from what is described with regard to.

4 FIG. 136 136 200 300 400 is a diagram illustrating an example of the automated bleed-off system. As described herein, the automated bleed-off systemmay include the bleed-off manifold, the valve greasing system, and the control system.

300 302 214 216 218 220 200 300 304 214 216 218 220 302 300 306 302 304 300 304 The valve greasing systemmay include a grease reservoirto hold a quantity of grease used for greasing the isolation valves,,,of the bleed-off manifold. The valve greasing systemmay include a plurality of grease conduitsin fluid communication with the isolation valves,,,and fluidly coupled to the grease reservoir. The valve greasing systemmay include a pumpconfigured to pump grease from the grease reservoirthrough the grease conduits. The valve greasing systemmay additionally include one or more valves (not shown) for controlling the flow of grease through the grease conduits.

400 214 216 218 220 300 402 400 222 224 404 404 404 406 222 406 222 404 406 4 FIG. 4 FIG. The control systemmay provide control over actuation of the isolation valves,,,as well as over the valve greasing system. In addition to the controller(e.g., which may be implemented as a single controller or multiple controllers), the control systemmay include the valve actuators(only one shown in), the actuation sensors(only one shown in), and an actuation system. The actuation systemis described herein as a hydraulic system, but may be another type of system, such as a pneumatic system or an electrically actuated system. The actuation systemmay include a plurality of fluid conduitsconnected to the valve actuators. The fluid conduitsmay be used to carry hydraulic fluid for controlling the valve actuators. The actuation systemmay additionally include one or more valves (not shown), one or more pressure tanks (not shown), one or more pumps (not shown), one or more fluid reservoirs (not shown), or the like, for controlling the flow of hydraulic fluid through the fluid conduits.

402 402 The controllermay include one or more memories and one or more processors communicatively coupled to the one or more memories. A processor may include a central processing unit, a graphics processing unit, a microprocessor, a controller, a microcontroller, a digital signal processor, a field-programmable gate array, an application-specific integrated circuit, and/or another type of processing component. The processor may be implemented in hardware, firmware, or a combination of hardware and software. The processor may be capable of being programmed to perform one or more operations or processes described elsewhere herein. A memory may include volatile and/or nonvolatile memory. For example, the memory may include random access memory (RAM), read only memory (ROM), a hard disk drive, and/or another type of memory (e.g., a flash memory, a magnetic memory, and/or an optical memory). The memory may be a non-transitory computer-readable medium. The memory may store information, one or more instructions, and/or software (e.g., one or more software applications) related to the operation of the controller.

222 224 404 404 402 402 402 130 104 100 402 136 104 130 The valve actuators, the actuation sensors, and/or the actuation system(e.g., a controller of the actuation system) may be communicatively coupled to the controller(e.g., through a wired connection or wirelessly) to enable the transmission of information to and from the controller. In some examples, the controllermay be communicatively coupled to the controllerto enable the exchange of information relating to one or more pump systemsof the hydraulic fracturing system. In some examples, the controllermay be communicatively coupled to an operator interface (e.g., an operator interface of the automated bleed-off system, or an operator interface of a pump systemvia the controller).

136 140 140 136 136 140 404 136 In some implementations, the automated bleed-off systemmay include a battery. The batterymay provide a backup power source for the automated bleed-off systemin the event that power from an external power source (e.g., a utility grid, a generator, a solar power system, etc.) is lost. When the automated bleed-off systemis receiving power from the external power source, the batterycan be charged and one or more pressure tanks (not shown) of the actuation systemcan be pressurized (e.g., by a pump), thus allowing the core functionality of the automated bleed-off systemto be continued during power outages.

402 402 100 100 100 402 402 100 402 104 130 104 100 The controllermay be configured to perform operations providing automated pressure bleed-off, automated system flushing, and/or automated valve greasing. In connection with automated pressure bleed-off, the controllermay receive an instruction (e.g., via an operator interface) to bleed-off pressure from the hydraulic fracturing system. The instruction may indicate whether the pressure is to be bled from the pump side of the hydraulic fracturing systemor the well side of the hydraulic fracturing system. The controllermay receive the instruction between stages of a hydraulic fracturing operation (e.g., after completion of a stage of the hydraulic fracturing operation). In other examples, the controllermay make a determination to bleed-off pressure from the hydraulic fracturing system. For example, the controllermay detect the completion of a stage of a hydraulic fracturing operation (e.g., based on information relating to one or more pump systemsreceived from the controller, such as a current discharge pressure of the pump system(s)), which corresponds to a time when pressure is to bled from the hydraulic fracturing system.

402 214 216 218 220 210 206 100 130 214 202 218 206 216 220 100 130 216 204 218 206 214 220 100 130 216 204 132 218 206 214 220 100 130 214 216 218 206 220 130 228 228 402 Responsive to the instruction and/or a determination to bleed-off pressure, the controllermay cause actuation (e.g., opening) of multiple of the isolation valves,,,to bleed-off pressure via the multi-stage choke assemblyin the bleed-off line. For example, to bleed-off pressure from the pump side of the hydraulic fracturing system, the controllermay cause actuation (e.g., opening) of the first isolation valve(allowing flow through the first fluid input) and actuation (e.g., opening) of the third isolation valve(allowing flow through the bleed-off line), while the second and fourth isolation valves,remain closed. As another example, to bleed-off pressure from the well side of the hydraulic fracturing system, the controllermay cause actuation (e.g., opening) of the second isolation valve(allowing flow through the second fluid input) and actuation (e.g., opening) of the third isolation valve(allowing flow through the bleed-off line), while the first and fourth isolation valves,remain closed. In some examples, to bleed-off pressure from both the pump side and the well side of the hydraulic fracturing system, the controllermay cause actuation (e.g., opening) of the second isolation valve(allowing flow through the second fluid input, which may also cause pressure in the pump side to equalize through the valve) and actuation (e.g., opening) of the third isolation valve(allowing flow through the bleed-off line), while the first and fourth isolation valves,remain closed. In some examples, to bleed-off pressure from both the pump side and the well side of the hydraulic fracturing system, the controllermay cause actuation (e.g., opening) of both the first isolation valveand the second isolation valve(e.g., concurrently), and actuation (e.g., opening) of the third isolation valve(allowing flow through the bleed-off line), while the fourth isolation valveremains closed. During a bleed-off operation, the controllermay monitor readings from the first pressure sensorand/or the second pressure sensorto detect when a target or threshold pressure (e.g., zero pressure or a wellhead pressure) is reached, at which time the controllermay terminate the bleed-off operation (e.g., by causing closing of the open valves).

130 100 130 100 100 100 130 100 130 100 In connection with automated system flushing, the controllermay receive an instruction and/or make a determination to flush the hydraulic fracturing system, in a similar manner as described for the automated pressure bleed-off. For example, the controllermay determine to flush the hydraulic fracturing systembased on detecting excessive proppant in the hydraulic fracturing systemand/or based on detecting unexpected pressures in the hydraulic fracturing system(e.g., which may indicate a proppant build up). As another example, the controllermay determine to flush the hydraulic fracturing systemin connection with performing a pressure bleed-off operation. For example, the controllermay determine to flush the hydraulic fracturing systemafter performing the pressure bleed-off operation.

100 402 214 216 218 220 212 100 130 214 202 220 212 216 218 402 Responsive to the instruction and/or a determination to flush the hydraulic fracturing system, the controllermay cause actuation (e.g., opening) of multiple of the isolation valves,,,to flush fluid via the bypass line. For example, to flush the pump side of the hydraulic fracturing system, the controllermay cause actuation (e.g., opening) of the first isolation valve(allowing flow through the first fluid input) and actuation (e.g., opening) of the fourth isolation valve(allowing flow through the bypass line), while the second and third isolation valves,remain closed. The controllermay terminate the flushing operation after a set time period or upon receiving an instruction to terminate the flushing operation.

130 214 216 218 220 214 216 218 220 214 216 218 220 200 200 130 228 228 228 The controllermay also execute other operations by causing actuation of one or more of the isolation valves,,,. For example, other operations may include closing all isolation valves,,,, opening all isolation valves,,,(e.g., for transport or rig down), priming the bleed-off manifoldto a test pressure, performing a pressure test of the bleed-off manifold(e.g., to check for leaks), and/or a combination operation that includes the prime up, the pressure test, and a bleed-off to the wellhead. In connection with one or more of these operations, the controllermay monitor pressure at the first pressure sensor, the second pressure sensor, and/or the third pressure sensor(e.g., monitor pressure increases, pressure drops, pressure differentials, or the like).

130 224 214 216 218 220 130 214 216 218 220 300 130 214 216 218 220 214 216 218 220 130 130 300 130 306 300 304 130 214 216 218 220 In connection with automated valve greasing, the controllermay monitor, using the actuation sensors, respective valve actuation histories for each of the isolation valves,,,, and the controllermay cause, based on the valve actuation histories, one or more of the isolation valves,,,to be greased using the valve greasing system. For example, the controllermay keep a count of the number of times each of the isolation valves,,,has been actuated (e.g., opened and/or closed) since a previous greasing. Following an operation involving actuation of an isolation valve,,,, as described herein, the controllermay determine whether the count of the number of actuations for that isolation valve meets a threshold (e.g., six actuations), thereby indicating that greasing is needed. If the count meets the threshold, then the controllermay cause the isolation valve to be greased using the valve greasing system. In particular, the controllermay cause the pumpof the valve greasing systemto pump grease through a grease conduitto the isolation valve. In some examples, the controllermay cause actuation of the isolation valve (e.g., repetitive opening and closing) during greasing to improve an application of the grease. In some examples, all of the isolation valves,,,may be greased if any one of the isolation valves is due for greasing.

4 FIG. 4 FIG. As indicated above,is provided as an example. Other examples may differ from what is described with regard to.

5 FIG. 5 FIG. 5 FIG. 500 402 136 130 500 is a flowchart of an example processassociated with automated pressure bleed-off. One or more process blocks ofmay be performed by a controller (e.g., controller). Additionally, or alternatively, one or more process blocks ofmay be performed by another device or a group of devices separate from or including the controller, such as another device or component that is internal or external to the automated bleed-off system(e.g., controller). Processmay relate to automated bleed-off of fluid pressure from a hydraulic fracturing system between stages of a hydraulic fracturing operation.

500 510 402 Processmay include, at step, obtaining (e.g., using one or more memories, one or more processors, and/or a communication component of controller), after completion of a stage of the hydraulic fracturing operation, an instruction to bleed-off pressure from the hydraulic fracturing system.

500 520 402 222 Processmay include, at step, causing (e.g., using one or more memories, one or more processors, a communication component of controller, and/or a valve actuator) opening of multiple isolation valves of a bleed-off manifold to bleed-off pressure via a multi-stage choke assembly in a bleed-off line of the bleed-off manifold.

500 402 224 402 500 402 In some examples, processmay further include monitoring (e.g., using one or more memories, one or more processors of controller, and/or an actuation sensor) a valve actuation history of an isolation valve, and causing (e.g., using one or more memories, one or more processors, and/or a communication component of controller), based on the valve actuation history, the isolation valve to be greased using a valve greasing system that includes a grease conduit fluidly coupled to the isolation valve. In some examples, processmay further include causing (e.g., using one or more memories, one or more processors, and/or a communication component of controller) opening of different multiple isolation valves of the bleed-off manifold to flush fluid through a bypass line of the bleed-off manifold that bypasses the multi-stage choke assembly.

5 FIG. 5 FIG. 500 500 500 Althoughshows example blocks of process, in some implementations, processmay include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in. Additionally, or alternatively, two or more of the blocks of processmay be performed in parallel.

136 136 The automated bleed-off systemdescribed herein may be used with any system that contains high-pressure fluid. For example, the automated bleed-off systemmay be used with a hydraulic fracturing system for recovery of water, oil, natural gas, and/or other fluids from a rock formation. In a hydraulic fracturing operation, pressurized fluid and proppants may be pumped into the wellbore in a series of stages. Following a stage, the pressurized fluid may be bled from the system to allow for various wireline activities to be performed in the wellbore. Generally, in a bleed-off operation, one or more valves are manually opened and closed when a target pressure is reached. This manual approach is imprecise and inconsistent, which can lead to unintended rapid depressurization and damage to components of the hydraulic fracturing system. Moreover, the valves should receive frequent greasing to improve their longevity. However, a timing for greasing the valves is often subject to operator discretion, which can result in lengthy intervals between greasings that can shorten a useful life of the valves.

136 136 200 136 210 210 136 The automated bleed-off systemdescribed herein provides automated pressure bleed-off as well as automated valve greasing. In particular, the automated bleed-off systemmay perform a pressure bleed-off using a sequence of valve openings with high precision and consistency. This high precision and consistency of the automated pressure bleed-off reduces unintended rapid depressurization events, thereby preventing damage and extending the useful life of components of a hydraulic fracturing system. Moreover, the bleed-off manifoldof the automated bleed-off systemincludes a multi-stage choke assemblythat provides a gradual pressure release that reduces stress on components of the hydraulic fracturing system and extends a useful life of the chokes of the multi-stage choke assembly. In addition, the automated bleed-off systemmay perform valve greasing at regular intervals, thereby ensuring proper greasing of valves and extending their useful lives.

The foregoing describes only some embodiments, and alterations, modifications, additions and/or changes can be made thereto without departing from the scope and spirit of the disclosed embodiments, the embodiments being illustrative and not restrictive. Furthermore, implementations are not limited to the disclosed embodiments, and may cover various modifications and equivalent arrangements included within the spirit and scope of the disclosed embodiments. Also, the various embodiments described above may be implemented in conjunction with other embodiments, for example, aspects of one embodiment may be combined with aspects of another embodiment to realize yet other embodiments. Further, each independent feature or component of any given assembly or process may constitute an additional embodiment. As used herein, the singular forms of “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. In addition, as used herein, the term “or” means “and/or” unless the context clearly dictates otherwise.

When “a controller” or “one or more controllers” is described or claimed (within a single claim or across multiple claims) as performing multiple operations or being configured to perform multiple operations, unless described or claimed otherwise (e.g., via the use of “first controller” and “second controller” or other language that differentiates controllers) this language is intended to cover a single controller performing or being configured to perform all of the operations, a group of controllers collectively performing or being configured to perform all of the operations, a first controller performing or being configured to perform a first operation and a second controller performing or being configured to perform a second operation, or any combination of controllers performing or being configured to perform the operations.